Safety switch apparatus



Jan. 5, 1943. s. E. BOYN I'ON ETAL SAFETY SWITCH APPARATUS Filed July 13, 1939 2 Sheets-She'et i INVENTORS $.E. BOYNTON 0. v; WA TERS ATTORNEY Jan. 5, 1943.

S. E. BOYNTON ETAL SAFETY SWITCH APPARATUS 2 Sheets-Sheet 2 Filed July 13, 1939 INVENTORS S. E. BOYNTON D. M WA TEPS- ATTORNEY the operator to stand the line 22 of Fig.

Patented Jan. 5, 1943 I 2,307,383 SAFETY SWITCH APPARATUS Stanley E. Boynton, Westfield, and Daniel V.

Waters, South Orange, N. J

assignors to Western Electric Company, Incorporated, New York,

N. Y., a corporation of New York Application July 13, 1939, Serial No. 284,168 2 Claims. (CL 192-129) This invention relates to safety switch apparatus, and more particularly to safety switch apparatus for use upon boring or other types of machines.

In large boring machines, for example, those having rotary work supporting tables necessitating a platform in substantially the same plane with the rotary table to support an operator while carrying out his duties in preparing machines of this type for operation and during the operation of such machines, it is sometimes necessary for upon the work supporting table. Due to the size of such machines it is not possible to position the conventional switch buttons for the circuits to motors driving the table and the boring tools so that an operator can reach them from all positions in which he might be standing.

An object of the invention is to provide a simple, efiicient and practical safety switch apparatus for machines convenient for actuation by an operator at various positions with respect to the machine to stop their actuation.

With this and other objects in view, the invention comprises keyed upon a shaft and rotatable in either direction to rotate the shaft through the movement of a hand operated lever to substantially instantaneously cause actuation of a switch to open any or all circuits to the power means for operating a machine with which the safety switch apparatus is associated.

Other objects and advantages will be apparent from the following detailed description when con; sidered in conjunction with the accompanying drawings, wherein Fig. 1 is a top plan view of the safety switch apparatus associated with a boring machine;

Fig. 2 is a vertical sectional view taken along Fig. 3 is an enlarged fragmentary detailed view of the switch operating mechanism taken along the line 3-3 of Fig. 1;

Fig. 4 is an enlarged fragmentary detailed view taken along the line 44 of Fig. 1, and

Fig. 5 is a wiring diagram illustrating circuits controlled by the apparatus.

To illustrate the invention it is shown in conjunction with a large boring machine, the general features of which will be described first. The boring machine, indicated generally at l 0 in Figs. 1 and 2, has a large work supporting table II mounted for rotation and conditioned for the mounting of articles, such as the cylinder l2, thereon for boring. The table I I is driven in a :a quick operating arm slidably clockwise direction (Fig. 3) by a motor l4 and suitable mechanism (not shown) operatively connecting the motor to the table. In this type of boring machine two boring heads I5 and I6 are mounted, as at I 1, for lateral adjustment relative to the table for the positioning of tools I 8 in desired positions with respect to the cylinder [2 mounted upon the table. Each tool I8 is removably secured in a chuck l9 mounted upon'the lower end of its reciprocable member 20. The reciprocable members 20 are movably disposed in cylindrical portions of the head and are each provided with rack portions 22 operatively connected through means (not shown) to speed reducing mechanism 24 and through a shaft 25, a gear 26, a pinion 21, to a motor 28. It is not believed important to show in detail all the mechanism of the boring machine H) or to describe completely its structure and operation. The teen tures of interest to illustrate the invention are the work supporting table I l, sufficiently large in diameter to support large articles, the position of the boring heads, and in general the power means, such as the motors l4 and 28, for respectively driving the table and the boring heads.

With the machines of this type it is sometimes necessary that a platform, such as that indicated at 30, provided with suitable steps 3| and a guard rail 32 and curved, as at 33, to conform somewhat to the table, be provided for supporting the operator.

The control switches for the electrical circuits of the motors are usually positioned at a suitable place on the machine, but due to the size of the macihne it is possible for the operator to be in positions, regardless of where the switches may be mounted, where he would not be able to reach the switches should an accident occur. In machines of this type the table II is approximately five feet in diameter and the length of the support for the adjusting of the boring heads is approximately twelve feet. Frequently it is necessary for the operator to step upon the table II during operation of the machine to make certain adjustments and during such times he is not in a position to actuate switches to deenergize the motors. Therefore, a safety switch apparatus is shown where he might be standing within the dangerous area around the table II or the boring heads 15 and i6.

The safety switch apparatus includes switches 35 and 36 mounted at the extreme sides of the machine, preferably on the support for the boring heads l5 and I6. The inner details of the switches are not shown but can be of any suitable type, for example, each having stationary contacts and movable contacts, the latter being insulated from but operatively connected to a lever 31, pivotally supported at 38 upon the outside of a casing 39 housing the contacts. The lower end of each lever 31 supports a roller 40 (Fig. 4) positioned to rest in a recess 4| of a switch arm or cam 42 having actuating surfaces or raised portions 43 upon each side of the recess to cause the roller 40 to ride thereupon upon movement of each cam in either direction to rock the lever 3'! and thus move the contacts associated therewith into open positions. Suitable means (not shown) normally urges each lever in a direction, for example, clockwise, viewing Fig. 4, to hold the roller 48 in intimate engagement with the cam 42.

The cams 42 are rigidly mounted upon the ends of a shaft 45, the latter being supported by any suitable bearings, such as those indicated at 46, supported by the boring heads 15 and H5. The shaft 45 is longitudinally grooved, providing a keyway for the connection of arms 48 thereto. By viewing Figs. 1 and 3 it will be observed that the inner ends of arms 48 have boss-like portions slidably mounted upon the shaft for lateral adjustment with their respective boring head, yet due to a key 49 of ach arm, rotary movement of either arm about the axis of the shaft 45 will cause rotation of the shaft.

The means for moving the arms 48 consist of hand levers 52 pivotally supported at 53 upon brackets 54 rigidly mounted upon the boring heads l5 and IS, the inner ends of the levers 52 carrying pins 55 receivable in elongate apertures 56 in the outer ends of the arms 48 to thus operatively connect the hand levers to their respective arms. The outer ends of the hand levers have handles 58 in opposite directions and in front of their respective boring heads.

Referring now to the electrical circuits in Fig. 5 for the motors l4 and 28, it is to be understood that the motors are equipped with brakes of the spring pressed disk type rendered ineffective by solenoids, illustrated by the coils 59, when the motor circuits are closed, and in each motor circuit a magnetic contactor is disposed. The magnetic contactors are illustrated at 66 and 6! for the circuits of the motors I4 and 28, respectively. Any suitable switch may be provided for each circuit, such as the conventional type push button switches 62 and 63 shown schematically in Fig. 5. When the switches 62 and 63 are closed and the switches 35 and 36 are closed, the circuit to the motor l4 may be traced from a lead 65 through switch 35, magnetic contactor 60, switch 62, motor [4, to lead 66. With the same arrangement of switches the circuit to the motor 28 may be traced from lead 65 through switch 36, magnetic contactor 6|, switch 63, motor 28, and lead 66. It is, therefore, apparent that when either or both circuits are closed to either or both motors the actuation of the shaft 45 to open both switches 35 and 36 will deenergize either or both motors and the solenoid coils 59 to instantly allow actuation of the motor brakes to stop the motors.

Referring now to the operation of the apparatus, let it be assumed that the cylinder I2 has been mounted upon the table II for coaxial rotation therewith. At this time the machine is at rest, with both motors deenergized, and one or both of the boring heads may be moved into desired boring positions to position the tools carried thereby adjacent the outer or inner peripheries of the cylinder. In the present instance only one boring tool is shown in operating position and in moving this unit into such position it is necessary for the operator to stand upon the table II to make the necessary adjustments. After the cylinder has been secured upon the table and the boring head 16 properly located with respect to the cylinder the switches 62 and 63 may be closed and with the switches 35 and 36 in their normally closed positions the motor l4 will be deenergized to rotate the table and the motor 28 will be energized to cause vertical movement of the boring head l6.

If the circuits should he accidentally closed during the positioning of the boring head the operator might be injured before he is able to actuate the switch 62 or switch 63 and if the operator should be standing out of reach of the switches 62 and 63 he might be seriously injured before help could arrive to actuate the switches. Therefore, the positioning of the hand levers 52 adjacent the danger zones and with long handles extending for some distance in front of each danger zone, that is, in front of the boring heads, where it is most likely that an operator might be injured, it is possible for the operator, regardless of the position in which he is standing, to open the circuits to either or both motors substantially instantaneously. The levers 52, their arms 48, and the shaft 45 are normally positioned to lock the cams 42 for the reception of the rollers 46 in the recesses 4! to normally allow the switches 35 and 36 to be in closed positions. This enables the operator to carry out the operation of the machine in the usual manner, that is, the starting and stopping of the motors through actuation of the switches 62 and 63, and unless something unexpected happens to endanger the operator it is not necessary for the operator to perform any additional duties, such as the setting of the safety switch mechanism. However, should such an occasion arise the operator may select either lever 52, or rather the handles 58 carried thereby, and with a slight movement in either direction the shaft 45 will be rotated either clockwise or counterclockwise, viewing Fig. 4, to cause the rollers 40 of both switches to leave the recesses 4| and ride upon the high portions 43 of the cam on one side or the other of each recess. This movement of the cams, however slight, instantly moves the levers 31 on both switches to move the contacts of the switches associated therewith into open positions. Therefore, the rapid or substantially instantaneous movement of the switches into open positions will affect the magnetic contactors to instantaneously deenergize the motor I4 and/or 28, and due to their brakes the motors will be stopped substantially instantaneously. Only in such instances is it necessary to set the safety switch mechanism before it is possible to again energize the motors through the closing of the switches 62 and 63.

It will be apparent, by viewing Figs. 1 and 2, that each actuating means for the switches 35 and 36, namely the levers 52 with their handles 58 and the arms 48, are positioned so that they will not interfere with the adjustment of the boring heads or the operation of the machine and are mounted for movement with their respective boring heads so that at all times, regardless of the size of article on the table or the positions of the boring heads, these portions of relative movement of the the switch actuating mechanism are adjacent the danger zones and within reach of the operator regardless of his position. Furthermore, the mounting of the levers 52 and the arms 48 for movement of their respective boring heads makes possible the adjustment of each set of levers and arms with their boring heads without any additional effort on th part of the operator. The adjustment of the switch controlling apparatus is, therefore, automatic with the adjustment of the machine, that, is, with the adjustment of the boring heads. Therefore, without additional lever for the operator he may carry out his same duties in operating the machine and preparing it for operation without additional efiort or thought regarding the safety switch mechanism this mechanism will at all times be present mainly at the danger :zones but within reach of the operator at any position.

The embodiment of the invention herein disclosed is illustrative only and may be widely modified and departed from in many ways without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

l. The combination with a material working machine having a material working unit supported for adjustment into a plurality of positions, a support for a material, a motor to cause unit and the support and an electrical circuit for the motor, of a safety switch apparatus comprising a fixed position switch disposed in the circuit, an element formed to hold the said switch closed, when in a normal position, and to open the switch when moved in any of a plurality of directions out of the normal position, a movable member to support the element, and means manually actuable in different directions operatively connected to the member and mounted to follow the unit into its adjusted positions to cause the element to move in any one of the directions out of the normal position to open the switch and thus open the circuit to the motor.

2. The combination with a material working machine having a material working unit supported for adjustment into a plurality of posi-. tions, a support for a material, a motor to cause relative movement of the unit and the support and an electrical circuit for the motor, of a safety switch apparatus comprising a fixed position switch disposed in the circuit and having a portion movable between a normal or closed position and an open position, an element having a recess therein to receive the said portion when in the normal position to hold the switch closed and adapted to move the portion out of the recess and into the open position when moved in any of a plurality of directions, a movable member to support the element, and means manually actuable in difierent directions operatively connected to the member and mounted to follow the unit into its adjusted positions to cause the element to move in any one of the directions out of the normal position to open the switch and thus open the circuit to the motor.

STANLEY E. BOYNTON. DANIEL V. WATERS. 

